ogg theora vorbis badly out-of-sync

Description

​http://thread.gmane.org/gmane.comp.video.mplayer.devel/59554/focus=59565
When attached sample is transcoded with ffmpeg, output is completely out-of-sync, as is playback with ffplay and mplayer -demuxer lavf (and -demuxer ogg).
The sample plays fine with firefox (and much better with vlc than with MPlayer/FFmpeg).
The sample contains 100 frames and should play for 33 seconds (24 fps look wrong).